【摘要】：我國(guó)苜蓿主要種植在鹽漬化地區(qū),鹽漬化土壤是造成苜蓿產(chǎn)量較低且不穩(wěn)定的重要因素。因此,研究鹽脅迫對(duì)苜蓿耐鹽生理指標(biāo)的影響及探索有效的抗鹽調(diào)控措施,為提高苜蓿鮮草、干草產(chǎn)量提供實(shí)踐支持與理論依據(jù)。本研究采用培養(yǎng)皿發(fā)芽、盆栽和大田試驗(yàn)相結(jié)合的方法,研究鹽脅迫對(duì)苜蓿各生育時(shí)期的耐鹽特性、光合特性及刈割產(chǎn)量的影響,以及不同種植模式、品種選擇等措施對(duì)苜蓿耐鹽性、器官物質(zhì)分配、鮮干草產(chǎn)量的調(diào)控作用。主要的研究結(jié)果如下：1.25個(gè)苜蓿品種中,中草3號(hào)、苜蓿王、新牧2號(hào)、康賽的種子發(fā)芽率、相對(duì)發(fā)芽指數(shù)、相對(duì)簡(jiǎn)易活力指數(shù)值較高,質(zhì)膜透性、丙二醛含量較低,脯氨酸、SOD活性較高,耐鹽性較強(qiáng)；中苜1號(hào)、Salt Buster、勇士表現(xiàn)相反,耐鹽性較差。0.80%鹽濃度為各項(xiàng)指標(biāo)變化的“拐點(diǎn)”,綜合分析苜蓿種子發(fā)芽指標(biāo)及耐鹽生理特性的聚類圖譜,將苜蓿種子劃分為三類,第一類包括中草3號(hào)、新牧2號(hào)、Nordica、黃花苜蓿、康賽,屬耐鹽性品種,第二類包括赤草1號(hào)、中苜1號(hào)、挑戰(zhàn)者、Salt Buster、勇士,屬敏感性品種,第三類包括2010,為中間型品種。2.凈光合速率與蒸騰速率日變化呈現(xiàn)單峰曲線變化,11：00時(shí)達(dá)峰值,17：00時(shí)值最低；質(zhì)膜透性、丙二醛含量、SOD活性、CAT活性和脯氨酸含量隨苜蓿生育時(shí)期的推進(jìn)逐漸增大,除CAT活性外其他生理指標(biāo)隨鹽濃度的遞增基本呈逐漸增加的趨勢(shì),以降低鹽脅迫程度。但0.20%鹽濃度促進(jìn)了苜蓿的生長(zhǎng)發(fā)育,較其他處理增加了中草3號(hào)和中苜1號(hào)的株高、凈光合速率、蒸騰速率、氣孔導(dǎo)度,提高了苜蓿的SOD活性、CAT活性和脯氨酸含量,降低了中草3號(hào)和中苜1號(hào)的的質(zhì)膜透性和丙二醛含量,促進(jìn)了苜蓿的產(chǎn)量提高。0.80%鹽濃度處理對(duì)苜蓿造成了嚴(yán)重減產(chǎn),使中草3號(hào)和中苜1號(hào)分別減產(chǎn)42.29%和47.82%。中草3號(hào)比中苜1號(hào)表現(xiàn)出較強(qiáng)的耐鹽性。3.苜蓿生長(zhǎng)的初期以莖部物質(zhì)器官積累為主,之后葉部器官物質(zhì)的積累幅度變大,開(kāi)花期后逐漸向花部轉(zhuǎn)移。混作處理增加了葉片葉綠素含量、鮮草重、干草重,提高了光合速率、蒸騰速率和氣孔導(dǎo)度。中草3號(hào)與老芒麥混作效果最好,表現(xiàn)出明顯的增產(chǎn)優(yōu)勢(shì)。2014年第一次刈割時(shí),與老芒麥混作的中草3號(hào)較單作中草3號(hào)和與無(wú)芒雀麥混作的中草3號(hào)的鮮草產(chǎn)量分別增加了9.05%和2.02%,干草產(chǎn)量分別增加了14.99%和1.99%；第二次刈割時(shí)鮮草產(chǎn)量分別增加了15.00%和21.95%;干草產(chǎn)量分別增加了1.99%和和2.09%。中草3號(hào)與無(wú)芒雀麥混作也獲得了相對(duì)較高的草產(chǎn)量。苜蓿與禾本科牧草混作有效提高了光合特性,增加了刈割產(chǎn)量。4.合理的間混作處理促進(jìn)了苜蓿干物質(zhì)積累、光合速率、蒸騰速率、氣孔導(dǎo)度的提高,增加了干草產(chǎn)量。1：1間作處理較1：2、1：3間作處理提高了苜蓿的光合速率、蒸騰速率、氣孔導(dǎo)度和干草產(chǎn)量。1：1間作處理中苜蓿邊行處理的光合速率較1：2、1：3和單作處理分別提高了25.60%、77.76%和132.00%,干草產(chǎn)量分別提高了28.57%、80.00%和200.00%,蒸騰速率和氣孔導(dǎo)度表現(xiàn)出相似的變化趨勢(shì)。5.苜蓿形態(tài)指標(biāo)、光合生理指標(biāo)、耐鹽生理指標(biāo)及鮮干草產(chǎn)量的相關(guān)性分析表明,苜蓿的干重、凈光合速率、蒸騰速率、胞間CO2濃度、SOD活性與產(chǎn)量呈極顯著正相關(guān)(P0.01),對(duì)刈割產(chǎn)量影響較大。苜蓿鮮干物質(zhì)向莖、花器官分配運(yùn)移,促進(jìn)苜蓿增產(chǎn)。
[Abstract]:Alfalfa is mainly planted in saline areas in China, and saline soil is an important factor causing low and unstable alfalfa yield. Therefore, the effects of salt stress on Physiological Indexes of salt tolerance of alfalfa and the effective control measures of salt tolerance were studied to provide practical support and theoretical basis for improving alfalfa fresh grass and hay yield. The effects of salt stress on salt tolerance, photosynthetic characteristics and cutting yield of Alfalfa at different growth stages, and the effects of different cultivation modes and varieties selection on salt tolerance, organ matter distribution and fresh hay yield of alfalfa were studied by dish germination, pot culture and field experiment. Among the varieties, Zhongcao No. 3, Alfalfa King, Xinmu No. 2, Kangsai had higher germination rate, relative germination index, relatively simple vigor index, lower plasma membrane permeability, lower malondialdehyde content, higher proline, SOD activity, stronger salt tolerance; Zhongcao No. 1, Salt Buster, Warrior showed the opposite, poor salt tolerance. "Inflection point" was used to analyze the clustering map of germination index and salt-tolerant physiological characteristics of Alfalfa seeds. The seeds of alfalfa were divided into three groups. The first group included Zhongcao No. 3, Xinmu No. 2, Nordica, Alfalfa, Kansai, which belonged to salt-tolerant varieties. The second group included Chicao No. 1, Zhongcao No. 1, Challenger, Salt Buster, Warrior, which belonged to sensitive varieties, and the third group was packed with salt tolerance. The diurnal variation of net photosynthetic rate and transpiration rate reached the peak at 11:00 and the lowest at 17:00. Plasma membrane permeability, malondialdehyde content, SOD activity, CAT activity and proline content gradually increased with the development of alfalfa, except CAT activity. However, 0.20% salt promoted the growth and development of alfalfa, increased the plant height, net photosynthetic rate, transpiration rate and stomatal conductance of Zhongcao 3 and Zhongmu 1, increased the SOD activity, CAT activity and proline content of alfalfa, and decreased Zhongcao 3 and Zhongmu 1 compared with other treatments. Membrane permeability and malondialdehyde content promoted alfalfa yield increase. 0.80% salt treatment caused serious yield reduction of alfalfa, resulting in 42.29% and 47.82% yield reduction of Zhongcao No. 3 and Zhongcao No. 1, respectively. Zhongcao No. 3 showed stronger salt tolerance than Zhongcao No. 1. 3. The accumulation of stem and leaf organs was dominant in the early stage of Alfalfa growth, and then the accumulation of leaf organs. Mixed cropping increased leaf chlorophyll content, fresh grass weight, hay weight, photosynthetic rate, transpiration rate and stomatal conductance. Mixed cropping of Zhongcao No. 3 and Old Mango showed the best effect and obvious yield-increasing advantage. Compared with single cropping Zhongcao 3 and mixed cropping Zhongcao 3, the yield of fresh grass increased by 9.05% and 2.02%, the yield of hay increased by 14.99% and 1.99%, the yield of fresh grass increased by 15.00% and 21.95% respectively, and the yield of hay increased by 1.99% and 2.09% respectively. Higher grass yield. Mixed cropping of alfalfa and grasses effectively improved photosynthetic characteristics and increased cutting yield. 4. Reasonable intercropping promoted dry matter accumulation, photosynthetic rate, transpiration rate, stomatal conductance of alfalfa, and increased hay yield. 1:1 intercropping treatment increased photosynthetic rate of Alfalfa compared with 1:2,1:3 intercropping treatment. The photosynthetic rate, transpiration rate, stomatal conductance and hay yield were increased by 25.60%, 77.76% and 132.00%, respectively, compared with 1:2, 1:3 and single cropping. The hay yield was increased by 28.57%, 80.00% and 200.00%, respectively. The transpiration rate and stomatal conductance showed a similar change trend. 5. The morphological index, photosynthesis of alfalfa. The correlation analysis of physiological index, salt tolerance physiological index and fresh hay yield showed that the dry weight, net photosynthetic rate, transpiration rate, intercellular CO2 concentration, SOD activity and yield of alfalfa were significantly positively correlated (P 0.01), which had a great influence on cutting yield.
【學(xué)位授予單位】：內(nèi)蒙古農(nóng)業(yè)大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2016
【分類號(hào)】：Q945.78
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本文編號(hào)：2219615